Influence of distribution of lean body mass on resting metabolic rate after weight loss and weight regain: comparison of responses in white and black women

24-h energy expenditure in people with type 1 diabetes: impact on equations for clinical estimation of energy expenditure

BACKGROUND/OBJECTIVES

Type 1 diabetes (T1D) is associated with an increase in resting metabolic rate (RMR), but the impact of T1D on other components of 24-h energy expenditure (24-h EE) is not known. Also, there is a lack of equations to estimate 24-h EE in patients with T1D. The aims of this analysis were to compare 24-h EE and its components in young adults with T1D and healthy controls across the spectrum of body mass index (BMI) and derive T1D-specific equations from clinical variables.

SUBJECTS/METHODS

Thirty-three young adults with T1D diagnosed ≥1 year prior and 33 healthy controls matched for sex, age and BMI were included in this analysis. We measured 24-h EE inside a whole room indirect calorimeter (WRIC) and body composition with dual x-ray absorptiometry.

RESULTS

Participants with T1D had significantly higher 24-h EE than healthy controls (T1D = 2047 ± 23 kcal/day vs control= 1908 ± 23 kcal/day; P < 0.01). We derived equations to estimate 24-h EE with both body composition (fat free mass + fat mass) and anthropometric (weight + height) models, which provided high coefficients of determination (R2 = 0.912 for both). A clinical model that did not incorporate spontaneous physical activity yielded high coefficients of determination as well (R2 = 0.897 and R2 = 0.880 for body composition and anthropometric models, respectively).

CONCLUSION

These results confirm that young adults with established T1D have increased 24-h EE relative to controls without T1D. The derived equations from clinically available variables can assist clinicians with energy prescriptions for weight management in patients with T1D.

The BREAK study protocol: Effects of intermittent energy restriction on adaptive thermogenesis during weight loss and its maintenance

BACKGROUND

Adaptive thermogenesis, defined as the decrease in the energy expenditure components beyond what can be predicted by changes in body mass stores, has been studied as a possible barrier to weight loss and weight maintenance. Intermittent energy restriction (IER), using energy balance refeeds, has been pointed out as a viable strategy to reduce adaptive thermogenesis and improve weight loss efficiency (greater weight loss per unit of energy deficit), as an alternative to a continuous energy restriction (CER). Following a randomized clinical trial design, the BREAK Study aims to compare the effects of IER versus CER on body composition and in adaptive thermogenesis, and understand whether participants will successfully maintain their weight loss after 12 months.

METHODS

Seventy-four women with obesity and inactive (20-45 y) will be randomized to 16 weeks of CER or IER (8x2 weeks of energy restriction interspersed with 7x1 week in energy balance). Both groups will start with 2 weeks in energy balance before energy restriction, followed by 16 weeks in energy restriction, then 8 weeks in energy balance and finally a 12-month weight maintenance phase. Primary outcomes are changes in fat-mass and adaptive thermogenesis after weight loss and weight maintenance. Secondary outcomes include weight loss, fat-free mass preservation, alterations in energy expenditure components, and changes in hormones (thyroid function, insulin, leptin, and cortisol).

DISCUSSION

We anticipate that The BREAK Study will allow us to better understand adaptive thermogenesis during weight loss and weight maintenance, in women with obesity. These findings will enable evidence-based decisions for obesity treatment.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT05184361.

Association between Variability of Metabolic Risk Factors and Cardiometabolic Outcomes

Despite strenuous efforts to reduce cardiovascular disease (CVD) risk by improving cardiometabolic risk factors, such as glucose and cholesterol levels, and blood pressure, there is still residual risk even in patients reaching treatment targets. Recently, researchers have begun to focus on the variability of metabolic variables to remove residual risks. Several clinical trials and cohort studies have reported a relationship between the variability of metabolic parameters and CVDs. Herein, we review the literature regarding the effect of metabolic factor variability and CVD risk, and describe possible mechanisms and potential treatment perspectives for reducing cardiometabolic risk factor variability.

The role of age in the physiological adaptations and psychological responses in bikini-physique competitor contest preparation: a case series

The increased popularity of the bikini-physique competitions has not translated to greater research identifying the influence of age on adaptations during contest preparation. The purpose of this case series was to observe how age may influence the adaptations normally seen during preparation and the exploration of newer protocols to address adaptations more relative to the judging standards. Over a 16-week pre-contest preparation, a 32-y bikini competitor (BC) and 44-y master's bikini competitor (MBC) visited the laboratory bi-weekly to observe changes in body fat mass (BF), lean body mass (LBM), bone mineral density (BMD), total body water (TBW); exploratory measures of deltoid cross-sectional area (DeltCSA), gluteus maximus muscle thickness (GMMT), and subcutaneous adipose tissue thickness (SAT); reproductive hormones estradiol (E2), luteinizing hormone (LH), and energy balance hormones triiodothyronine (T3), leptin and ghrelin; hydration status during contest preparation and the week of competition; resting metabolic rate (RMR); psychometric data related to perceived anxiety, stress, and body image were assessed. No differences between BC and MBC were observed in BF, LBM, BMD, and TBW. Both competitors showed a small loss in LBM. Both BC and MBC showed a contrasting increase in DeltCSA and a loss in GMMT. MBC showed to be slightly more dehydrated (1.025 vs 1.021 g·mL- 1) than BC. Both competitors maintained a euhydration status the day of the competition. No time differences were found between BC and MBC during RMR. BC showed a higher mean difference RMR compared to MBC (2.66 ± 0.75 kcal·kgLBM- 1·d- 1). MBC showed a higher mean difference in LH concentration (84.6 ± 6.01 IU·L- 1), which may be explained by perimenopausal status. MBC had a higher mean difference concentration of leptin (2.51 ± 0.24 ng·mL- 1·kgFM- 1), which was unperturbed by fat loss may be interrelated LH. BC self-reported a higher mean energy intake (15.07 ± 3.43 kcal·kgLBM- 1·d- 1) and higher aerobic training volume (93.26 ± 40.68 min·d). BC and MBC showed similar composition changes, slightly differing metabolic rates, and differing hormonal LH and leptin responses. This finding is in contrast to previous work showing both LH inhibition and leptin diurnal disturbance in younger, female athletes with low energy availability. The exploratory measures may have some benefit for bikini-physique competitors related to the judging criteria. Age did not seem to play a role in contest preparation adaptations.

Resting metabolic rate in adults with facioscapulohumeral muscular dystrophy

This study aimed to determine whether resting metabolic rate (RMR) is altered in adults with facioscapulohumeral muscular dystrophy (FSHD). Eleven people with FSHD (51 ± 12yrs, 2 females) and 11 controls (48 ± 14 yrs, 2 females) completed 1 visit, including 30-minutes of indirect calorimetry and dual-energy X-ray absorptiometry (DXA) scanning. RMR was calculated from resting oxygen consumption/carbon dioxide production; regional/whole-body fat mass and lean mass were collected from the DXA scan. Absolute RMR was 15% lower in FSHD (p = 0.04); when normalized to regional/local lean mass, no differences in RMR were observed (p > 0.05). Absolute RMR was correlated with total lean mass for all participants combined (p < 0.01, r = 0.70, males only: p < 0.01, r = 0.81) and when analyzed separately (FSHD males: p = 0.001, r = 0.92 and control males: p = 0.004, r = 0.85). Whole-body lean mass was 16% lower in FSHD and leg, arm and appendicular lean mass were lower in FSHD (p < 0.05 for all), though trunk lean mass was not (p = 0.15). Whole-body fat mass was 45% higher in FSHD, with greater leg fat mass (p = 0.01), but not trunk or arm fat mass (p > 0.05 for both). When RMR was expressed relative to lean body mass, no differences in RMR were found, indicating that the lower levels of lean mass observed in FSHD patients likely contribute to the lower absolute RMR values. Novelty: RMR is lower among people with FSHD, as compared with controls. The reduced RMR among people with FSHD is due to disease-related loss in muscle mass and likely related to lower physical activity and/or exercise levels.

From famine to therapeutic weight loss: Hunger, psychological responses, and energy balance-related behaviors

Understanding physiological and behavioral responses to energy imbalances is important for the management of overweight/obesity and undernutrition. Changes in body composition and physiological functions associated with energy imbalances provide the structural and functional context in which to consider psychological and behavioral responses. Compensatory changes in physiology and behavior are more pronounced in response to negative than positive energy balances. The physiological and psychological impact of weight loss (WL) occur on a continuum determined by (i) the degree of energy deficit (ED), (ii) its duration, (iii) body composition at the onset of the energy deficit, and (iv) the psychosocial environment in which it occurs. Therapeutic WL and famine/semistarvation both involve prolonged EDs, which are sometimes similar in magnitude. The key differences are that (i) the body mass index (BMI) of most famine victims is lower at the onset of the ED, (ii) therapeutic WL is intentional and (iii) famines are typically longer in duration (partly due to the voluntary nature of therapeutic WL and disengagement with WL interventions). The changes in psychological outcomes, motivation to eat, and energy intake in therapeutic WL are often modest (bearing in mind the nature of the measures used) and can be difficult to detect but are quantitatively significant over time. As WL progresses, these changes become more marked. It appears that extensive WL beyond 10%-20% in lean individuals has profound effects on body composition and physiological function. At this level of WL, there is a marked erosion of psychological functioning, which appears to run in parallel to WL. Psychological resources dwindle and become increasingly focused on alleviating escalating hunger and food seeking behavior. Functional changes in fat-free mass, characterized by catabolism of skeletal muscle and organs may be involved in the drive to eat associated with semistarvation. Higher levels of body fat mass may act as a buffer to protect fat-free mass, functional integrity and limit compensatory changes in energy balance behaviors. The increase in appetite that accompanies therapeutic WL appears to be very different to the intense and all-consuming drive to eat that occurs during prolonged semistarvation. The mechanisms may also differ but are not well understood, and longitudinal comparisons of the relationship between body structure, function, and behavior in response to differing EDs in those with higher and lower BMIs are currently lacking.

Effects of Cardiovascular Risk Factor Variability on Health Outcomes

Innumerable studies have suggested "the lower, the better" for cardiovascular risk factors, such as body weight, lipid profile, blood pressure, and blood glucose, in terms of health outcomes. However, excessively low levels of these parameters cause health problems, as seen in cachexia, hypoglycemia, and hypotension. Body weight fluctuation is related to mortality, diabetes, obesity, cardiovascular disease, and cancer, although contradictory findings have been reported. High lipid variability is associated with increased mortality and elevated risks of cardiovascular disease, diabetes, end-stage renal disease, and dementia. High blood pressure variability is associated with increased mortality, myocardial infarction, hospitalization, and dementia, which may be caused by hypotension. Furthermore, high glucose variability, which can be measured by continuous glucose monitoring systems or self-monitoring of blood glucose levels, is associated with increased mortality, microvascular and macrovascular complications of diabetes, and hypoglycemic events, leading to hospitalization. Variability in metabolic parameters could be affected by medications, such as statins, antihypertensives, and hypoglycemic agents, and changes in lifestyle patterns. However, other mechanisms modify the relationships between biological variability and various health outcomes. In this study, we review recent evidence regarding the role of variability in metabolic parameters and discuss the clinical implications of these findings.

Associations between the rate, amount, and composition of weight loss as predictors of spontaneous weight regain in adults achieving clinically significant weight loss: A systematic review and meta-regression

Weight regain following weight loss is common although little is known regarding the associations between amount, rate, and composition of weight loss and weight regain. Forty-three studies (52 groups; n = 2379) with longitudinal body composition measurements were identified in which weight loss (≥5%) and subsequent weight regain (≥2%) occurred. Data were synthesized for changes in weight and body composition. Meta-regression models were used to investigate associations between amount, rate, and composition of weight loss and weight regain. Individuals lost 10.9% of their body weight over 13 weeks composed of 19.6% fat-free mass, followed by a regain of 5.4% body weight over 44 weeks composed of 21.6% fat-free mass. Associations between the amount (P < 0.001) and rate (P = 0.049) of weight loss and their interaction (P = 0.042) with weight regain were observed. Fat-free mass (P = 0.017) and fat mass (P < 0.001) loss both predicted weight regain although the effect of fat-free mass was attenuated following adjustment. The amount (P < 0.001), but not the rate of weight loss (P = 0.150), was associated with fat-free mass loss. The amount and rate of weight loss were significant and interacting factors associated with weight regain. Loss of fat-free mass and fat mass explained greater variance in weight regain than weight loss alone.

Weight Cycling as a Risk Factor for Low Muscle Mass and Strength in a Population of Males and Females with Obesity

OBJECTIVE

This study aimed to determine whether multiple weight cycles in adulthood are an independent predictor of lower muscle mass and reduced strength, with potential implication for sarcopenia in adults with obesity.

METHODS

A total of 60 males and 147 females with obesity were included, with a mean BMI of 37.9 ± 6.0 kg/m² and a mean age of 52.6 ± 12.4 years. Muscle strength was evaluated with handgrip and appendicular skeletal muscle mass was measured with dual-energy x-ray absorptiometry.

RESULTS

Participants were categorized into the following three groups: non-weight cyclers, mild weight cyclers, and severe weight cyclers. From a binary logistic regression that considered muscle mass categories as a dependent variable and weight cycling categories, age, and sex as independent variables, severe weight cyclers showed a 3.8-times increased risk of low muscle mass (95% CI: 1.42-10.01). Considering handgrip strength categories as a dependent variable and weight cycling categories, age, sex, and BMI as independent variables, severe weight cycling was associated with an increased risk of low muscle mass (about 6.3 times, 95% CI: 1.96-20.59). Severe weight cyclers showed a 5.2-times greater risk of developing sarcopenia.

CONCLUSIONS

In adults with obesity, weight cycling is associated with lower muscle mass and strength and a greater likelihood of developing sarcopenic obesity.

Intermittent Dieting: Theoretical Considerations for the Athlete

Athletes utilise numerous strategies to reduce body weight or body fat prior to competition. The traditional approach requires continuous energy restriction (CER) for the entire weight loss phase (typically days to weeks). However, there is some suggestion that intermittent energy restriction (IER), which involves alternating periods of energy restriction with periods of greater energy intake (referred to as ‘refeeds’ or ‘diet breaks’) may result in superior weight loss outcomes than CER. This may be due to refeed periods causing transitory restoration of energy balance. Some studies indicate that intermittent periods of energy balance during energy restriction attenuate some of the adaptive responses that resist the continuation of weight and fat loss. While IER—like CER—is known to effectively reduce body fat in non-athletes, evidence for effectiveness of IER in athletic populations is lacking. This review provides theoretical considerations for successful body composition adjustment using IER, with discussion of how the limited existing evidence can be cautiously applied in athlete practice.

Continuous versus intermittent moderate energy restriction for increased fat mass loss and fat free mass retention in adult athletes: protocol for a randomised controlled trial-the ICECAP trial (Intermittent versus Continuous Energy restriction Compared in an Athlete Population)

Introduction

Reducing fat mass (FM) while retaining fat free mass (FFM) is a common goal of athletes. Evidence suggests that some-but not all-forms of intermittent energy restriction (IER) may be superior to the conventional method of continuous energy restriction (CER) for people with excess body fat that are sedentary, by reducing some of the adaptive responses to ER. However, it is yet to be established whether this dietary approach is effective for athletes.

Methods and analysis

A single-blind, parallel group, randomised controlled trial with a 1:1 allocation ratio is proposed. Sixty healthy athletes aged ≥18 years will be recruited from local sporting facilities and randomised to an intervention of either moderate CER (mCER) or moderate IER (mIER). Both interventions will consist of 12 weeks of moderate ER, plus 3 weeks in energy balance (EB). The mCER intervention will entail 12 weeks of continuous moderate ER, followed by 3 weeks in EB. The mIER intervention will entail 12 weeks of moderate ER, administered as 4×3 week blocks of moderate ER, interspersed with 3×1 week blocks of EB. The co-primary outcomes are changes in FM and FFM after 12 weeks of moderate ER. Secondary outcomes will be changes in FM and FFM at 15 weeks after intervention commencement, as well as muscle performance, physical activity, sleep quality, changes in resting energy expenditure, subjective drive to eat, circulating concentrations of appetite-regulating hormones, mood states and diet acceptability.

Trial registration

ACTRN12618000638235p.

Evaluating the contribution of differences in lean mass compartments for resting energy expenditure in African American and Caucasian American children

BACKGROUND

Resting energy expenditure (REE), adjusted for total lean mass (LM), is lower in African American (AA) than Caucasian American (CA) children. Some adult studies suggest that AA-CA differences in lean mass compartments explain this REE difference. Similar data are limited in children.

OBJECTIVE

To evaluate differences in compartment-specific lean mass between AA and CA children and examine the individual contributions of high-metabolic rate-at-rest trunk lean mass (TrLM) and low-metabolic-rate-at-rest appendicular lean mass (AppLM) for AA-CA differences in REE.

METHODS

We studied a convenience sample of 594 AA (n = 281) and CA (n = 313) children. REE was measured by using indirect calorimetry; dual-energy X-ray absorptiometry was used to assess body composition. ANCOVAs were performed to examine AA-CA differences in TrLM, AppLM and REE. After accounting for age, sex, height, pubertal development, bone mass and adiposity, REE was evaluated adjusting for total LM (model A) and separately adjusting for TrLM and AppLM (model B).

RESULTS

African American children had greater adjusted AppLM (17.8 ± 0.2 [SE] vs. 16.0 ± 0.2 kg, p < 0.001) and lower TrLM (17.2 ± 0.2 vs. 17.7 ± 0.2 kg, p = 0.022) than CA children. REE adjusted for total LM was 77 ± 16 kcal/d lower in AA than CA (p < 0.001). However, after accounting separately for AppLM and TrLM, the discrepancy in REE between the groups declined to 28 ± 19 kcal/d (p = 0.14). In the adjusted model, both TrLM (p < 0.001) and AppLM (p < 0.027) were independently associated with REE.

CONCLUSION

In children, AA-CA differences in REE appear mostly attributable to differences in body composition. Lower REE in AA children is likely due to lower TrLM and greater AppLM.

Increased risk of diabetes development in individuals with weight cycling over 4 years: The Kangbuk Samsung Health study

AIMS

Weight cycling is defined as cyclical loss and gain of weight and recent studies suggest deleterious effects of weight cycling on cardiometabolic health. We aimed to analyze the risk for diabetes development in association with weight cycling over 4 years of follow-up.

METHODS

A retrospective study performed in 4,818 non-diabetic participants (mean age 43 years, 78.3% men) in a health screening program in whom serial health examinations were performed in 5 consecutive years from 2010 to 2014. Average successive variability of weight (ASVW) was defined by the amount of body weight change in absolute value between the successive years over 5 years summed and divided by four. The subjects were divided into two groups according to body mass index (BMI), normal weight (<23 kg/m²) and overweight (≥23 kg/m²).

RESULTS

Over 4 years, 3.2% developed diabetes. When the subjects were divided into 3 groups according to tertile groups of ASVW, those in the highest tertile showed significantly increased risk for diabetes development compared to those with the lowest tertile {odds ratio (OR) 1.860; 95% CI 1.130-3.063}. When similar analyses were performed according to the 4 groups divided by baseline body weight and ASVW over four years, those who were more than overweight at baseline with high ASVW showed significantly increased risk of diabetes development compared to those had normal weight and low ASVW (OR 2.266; 95% 1.123-4.572). When the subjects were divided into six group according to weight change and ASVW, those with increased weight over 4 years and high ASVW showed the highest risk for diabetes development among the groups compared to those with stable weight and low ASVW over four years (OR 3.660; 95% CI 1.402-9.553).

CONCLUSIONS

Those with high ASVW showed significantly increased risk for diabetes development over four years compared with those who had low ASVW. Weight cycling was significantly associated with increased risk for diabetes.

Weight Cycling and Its Cardiometabolic Impact

Dieting has multiple meanings including "intentional weight loss" or "a specific eating pattern." Although obesity is considered a deleterious health problem worldwide, there are many problems caused by "too strict" weight control and the need for excessive leanness. Many people with normal weight want to lose weight, and they repeat losing and gaining weight multiple times through their lives. This is called "weight cycling." Recent studies report not just the negative impact of being obese, but also the danger of weight cycling for cardiometabolic health. Many experimental studies support that weight cycling might cause fluctuations in cardiovascular risk factors, such as blood pressure, heart rate, sympathetic activity, and circulating levels of glucose, lipids and insulin. These repeated overshoots above normal values during periods of weight regain put an additional stress on the cardiovascular system. This paper reviews current evidence for the effects of weight cycling on cardiometabolic health.

Intermittent energy restriction improves weight loss efficiency in obese men: the MATADOR study

Background/Objectives:

The MATADOR (Minimising Adaptive Thermogenesis And Deactivating Obesity Rebound) study examined whether intermittent energy restriction (ER) improved weight loss efficiency compared with continuous ER and, if so, whether intermittent ER attenuated compensatory responses associated with ER.

Subjects/Methods:

Fifty-one men with obesity were randomised to 16 weeks of either: (1) continuous (CON), or (2) intermittent (INT) ER completed as 8 × 2-week blocks of ER alternating with 7 × 2-week blocks of energy balance (30 weeks total). Forty-seven participants completed a 4-week baseline phase and commenced the intervention (CON: N=23, 39.4±6.8 years, 111.1±9.1 kg, 34.3±3.0 kgm⁻²; INT: N=24, 39.8±9.5 years, 110.2±13.8 kg, 34.1±4.0 kgm⁻²). During ER, energy intake was equivalent to 67% of weight maintenance requirements in both groups. Body weight, fat mass (FM), fat-free mass (FFM) and resting energy expenditure (REE) were measured throughout the study.

Results:

For the N=19 CON and N=17 INT who completed the intervention per protocol, weight loss was greater for INT (14.1±5.6 vs 9.1±2.9 kg; P<0.001). INT had greater FM loss (12.3±4.8 vs 8.0±4.2 kg; P<0.01), but FFM loss was similar (INT: 1.8±1.6 vs CON: 1.2±2.5 kg; P=0.4). Mean weight change during the 7 × 2-week INT energy balance blocks was minimal (0.0±0.3 kg). While reduction in absolute REE did not differ between groups (INT: -502±481 vs CON: −624±557 kJ d⁻¹; P=0.5), after adjusting for changes in body composition, it was significantly lower in INT (INT: −360±502 vs CON: −749±498 kJ d⁻¹; P<0.05).

Conclusions:

Greater weight and fat loss was achieved with intermittent ER. Interrupting ER with energy balance ‘rest periods’ may reduce compensatory metabolic responses and, in turn, improve weight loss efficiency.

Metabolic dysfunction following weight cycling in male mice

Background

Combatting over-weight or obesity can lead to large fluctuations in an individual’s body weight, often referred to as weight cycling or “yo-yo” dieting. Current evidence regarding the potentially damaging effects of these changes is conflicting.

Methods

Here, we assess the metabolic effects of weight cycling in a murine model, comprising three dietary switches to normal or high fat diets at 6 week intervals; male C57BL/6 mice were fed either a control (C) or high fat (F) diet for 6 weeks (n=140/group). C and F groups were then either maintained on their initial diet (CC and FF respectively) or switched to a high fat (CF) or control (FC) diet (n=35/group). For the final 6 week interval, CC and CF groups were returned to the control diet (CCC and CFC groups) while FC and FF groups were placed on a high fat diet (FCF and FFF) (n=28/group).

Results

For the majority of metabolic outcomes changes aligned with dietary switches; however assessment of neuropeptides and receptors involved in appetite regulation and reward signalling pathways reveal variable patterns of expression. Furthermore, we demonstrate that multiple cycling events leads to a significant increase in internal fat deposition, even when compared to animals maintained on a high fat diet (Internal Fat: FCF: 7.4 ± 0.2g vs. FFF: 5.6 ± 0.2g; p<0.01).

Conclusions

Increased internal adipose tissue is strongly linked to the development of metabolic syndrome associated conditions such as type 2 diabetes, cardiovascular disease and hypertension. While further work will be required to elucidate the mechanisms underlying the neuronal control of energy homeostasis, these studies provide a causative link between weight cycling and adverse health.

The functional and clinical outcomes of exercise training following a very low energy diet for severely obese women: study protocol for a randomised controlled trial

Background

Clinical practice guidelines globally recommend lifestyle modification including diet and exercise training as first-line treatment for obesity. The clinical benefits of exercise training in adults with obesity is well-documented; however, there is no strong evidence for the effectiveness of exercise training for weight loss in class II and class III obesity. The purpose of the randomised controlled trial described in this protocol article is to examine the effect of exercise training, in addition to a very low energy diet (VLED), in clinically severe obese women for changes in body composition, physical function, quality of life, and markers of cardiometabolic risk.

Methods/Design

Sixty women, aged 18–50 years with a body mass index (BMI) greater than 34.9 kg.m² and at least one obesity-related co-morbidity, will be recruited for this 12-month study. Participants will be randomised to either exercise plus energy restriction (n = 30), or energy restriction alone (n = 30). All participants will follow an energy-restricted individualised diet incorporating a VLED component. The exercise intervention group will also receive exercise by supervised aerobic and resistance training and a home-based exercise programme totalling 300 minutes per week. Primary outcome measures include body composition and aerobic fitness. Secondary outcome measures include: physical function, cardiometabolic risk factors, quality of life, physical activity, and mental health. All outcome measures will be conducted at baseline, 3, 6 and 12 months.

Discussion

Previous research demonstrates various health benefits of including exercise training as part of a healthy lifestyle at all BMI ranges. Although clinical practice guidelines recommend exercise training as part of first-line treatment for overweight and obesity, there are few studies that demonstrate the effectiveness of exercise in class II and class III obesity. The study aims to determine whether the addition of exercise training to a VLED provides more favourable improvements in body composition, physical function, quality of life, and markers of cardiometabolic risk for women with clinically severe obesity, compared to VLED alone.

Trial registration

Australian New Zealand Clinical Trials Registry (ACTRN12611000694910). Date registered: 4 July 2011

Deep body composition phenotyping during weight cycling: relevance to metabolic efficiency and metabolic risk

Weight cycling may lead to adverse effects on metabolic efficiency (i.e. adaptive thermogenesis or 'metabolic slowing') and metabolic risks (e.g. increased risk for insulin resistance and the metabolic syndrome). In order to investigate these topics, the partitioning of fat and lean mass (i.e. the change in the proportion of both compartments) needs to be extended to the organ and tissue level because metabolic risk differs between adipose tissue depots and lean mass is metabolically heterogeneous being composed of organs and tissues differing in metabolic rate. Contrary to data obtained with severe weight loss and regain in lean people, weight cycling most likely has no adverse effects on fat distribution and metabolic risk in obese patients. There is even evidence for an increased ability of fat storage in subcutaneous fat depots (at the trunk in men and at the limbs in women) with weight cycling that may provide a certain protection from ectopic lipid deposition and thus explain the preservation of a favourable metabolic profile despite weight regain. On the other hand, the mass-specific metabolic rate of lean mass may increase with weight gain and decrease with weight loss mainly because of an increase and respective decrease in the proportion (and/or activity) of metabolically active organ mass. Obese people could therefore have a higher slope of the regression line between resting energy expenditure (REE) and fat-free mass that leads to an overestimation of metabolic efficiency when applied to normalize REE data after weight loss. Furthermore, in addressing the impact of macronutrient composition of the diet on partitioning of lean and fat mass, and the old controversy about whether a calorie is a calorie, we discuss recent evidence in support of a low glycaemic weight maintenance diet in countering weight regain and challenge this concept for weight loss by proposing the opposite.

Treatment of body composition changes in obese and overweight older adults: insight into the phenotype of sarcopenic obesity

In recent years, mounting interest has been directed to sarcopenic obesity (SO), given the parallel increase of life expectancy and prevalence of obesity in Western countries. The phenotype of SO is characterized by the coexistence of excess fat mass and decreased muscle mass, leading to the impairment of physical performance. The aim of the present review was to summarize the impact of different treatment strategies contrasting body composition changes in older obese and overweight subjects, providing insight into the SO phenotype. Revision questions were formulated; relevant articles were identified from Pubmed through a systematic search strategy: definition of the search terms (sarcopenic obesity, diet, nutritional supplements, physical activity, exercise, pharmacological treatment); limits: papers published in the last 10 years; humans; age ≥ 60 years old; body mass index >25 kg/m(2); language: English. Studies dealing with sarcopenia associated to cancer cachexia or neurological diseases, any malignant disease, inflammatory or autoimmune diseases, corticosteroids for systemic use, bedridden subjects, and syndromic obesity were excluded. 14 articles were identified for inclusion in the present systematic review, and were grouped basing on the type of the main intervention: data assessing body composition changes after combined lifestyle interventions, exercise/physical activity, dietary interventions, and pharmacological treatment. Most of the studies were randomized, controlled. Sample size ranged from 12 to 439 subjects, and study duration varied from 6 weeks to 12 months. Weight loss based on diet combined with exercise seems to be the best strategy to adopt for treatment of phenotypic aspects of SO, improving metabolic consequences related to excess fat, preserving lean mass, and allowing functional recovery.

Measuring the impact of weight cycling on body composition: a methodological challenge

PURPOSE OF REVIEW

The impact of weight cycling on body composition and metabolic risk remains controversial. Very few studies, however, meet the methodological requirements to analyze and normalize changes in body composition with weight loss and regain.

RECENT FINDINGS

Methodological drawbacks that limit the interpretation of results are as follows:first, a small and only partial weight regain, second, the choice of an obese study population who experiences only small changes in fat-free mass, third, a lack of adjustment for the age-related decline in fat-free mass when examining elderly people and fourth, a lack of validity and precision of the body composition method that are important in a nonstable condition of weight loss and for measuring small changes in body composition. Normalization of changes in fat and lean mass for baseline body composition and measurement of fat and lean tissue distribution lead to further insights into the etiology and consequences of weight cycling.

SUMMARY

Current evidence does not support an adverse effect of weight cycling on body composition. By contrast, severe weight loss in normal-weight people that comprises a large loss of lean mass may shift the partitioning toward a transient higher regain in total and abdominal fat mass.

Identification of skeletal muscle mass depletion across age and BMI groups in health and disease--there is need for a unified definition

Although reduced skeletal muscle mass is a major predictor of impaired physical function and survival, it remains inconsistently diagnosed to a lack of standardized diagnostic approaches that is reflected by the variable combination of body composition indices and cutoffs. In this review, we summarized basic determinants of a normal lean mass (age, gender, fat mass, body region) and demonstrate limitations of different lean mass parameters as indices for skeletal muscle mass. A unique definition of lean mass depletion should be based on an indirect or direct measure of skeletal muscle mass normalized for height (fat-free mass index (FFMI), appendicular or lumbal skeletal muscle index (SMI)) in combination with fat mass. Age-specific reference values for FFMI or SMI are more advantageous because defining lean mass depletion on the basis of total FFMI or appendicular SMI could be misleading in the case of advanced age due to an increased contribution of connective tissue to lean mass. Mathematical modeling of a normal lean mass based on age, gender, fat mass, ethnicity and height can be used in the absence of risk-defined cutoffs to identify skeletal muscle mass depletion. This definition can be applied to identify different clinical phenotypes like sarcopenia, sarcopenic obesity or cachexia.

Resting energy expenditure and systolic blood pressure relationships in women across 4.5 years

Recent studies have reported a strong association between blood pressure (BP) and resting energy expenditure (REE). However, it is not known whether this relationship persists over time. Therefore, the authors examined the temporal relationship between REE and systolic BP. In addition, the impact of sympathetic tone and anthropometric variables on this relationship was examined. All testing was performed on healthy, overweight African American and European American women aged 25 to 45 years over 4.5 years in the University of Alabama at Birmingham General Clinical Research Center. Repeated-measures mixed-models revealed REE as a significant determinant of systolic BP (β=0.0155, P<.0001), independent of catecholamines, leg fat, visceral fat, fat-free mass, fat mass, height, relative skeletal muscle index, and resting heart rate. Observations that REE is predictive of systolic BP across 4.5 years support previous findings that REE may potentially mediate resting BP, independent of anthropometric variables and a marker for sympathetic tone.

The effects of exercise training in addition to energy restriction on functional capacities and body composition in obese adults during weight loss: a systematic review

BACKGROUND

Obesity is associated with impairments of physical function, cardiovascular fitness, muscle strength and the capacity to perform activities of daily living. This review examines the specific effects of exercise training in relation to body composition and physical function demonstrated by changes in cardiovascular fitness, and muscle strength when obese adults undergo energy restriction.

METHODS

Electronic databases were searched for randomised controlled trials comparing energy restriction plus exercise training to energy restriction alone. Studies published to May 2013 were included if they used multi-component methods for analysing body composition and assessed measures of fitness in obese adults.

RESULTS

Fourteen RCTs met the inclusion criteria. Heterogeneity of study characteristics prevented meta-analysis. Energy restriction plus exercise training was more effective than energy restriction alone for improving cardiovascular fitness, muscle strength, and increasing fat mass loss and preserving lean body mass, depending on the type of exercise training.

CONCLUSION

Adding exercise training to energy restriction for obese middle-aged and older individuals results in favourable changes to fitness and body composition. Whilst weight loss should be encouraged for obese individuals, exercise training should be included in lifestyle interventions as it offers additional benefits.

Regional, but not total, body composition changes in overweight and obese adults consuming a higher protein, energy-restricted diet are sex specific

Secondary analyses of data from 2 studies were used to assess the effects of protein intake and sex on diet-induced changes in body composition. The primary hypothesis was that the changes of body composition via energy restriction (ie, lean body mass [LBM], fat mass [FM], and bone) would be sex and diet specific. For 12 weeks, 43 male (study 1) and 45 female (study 2) overweight and obese adults consumed an energy-deficit diet (750 kcal/d less than energy needs) containing either 0.8 (normal protein [NP], 21 men and 23 women) or 1.4 g protein∙kg(-1)∙d(-1) (high protein [HP], 22 men and 22 women). Body composition measurements were performed at preintervention and postintervention. Over time, all research participants lost weight, LBM, and FM. Independent of protein intake, the men lost more LBM in the trunk (-0.9 vs -0.5 kg) and less in the legs (-1.5 vs -1.1 kg) compared with the women (P < .05). Independent of sex, the HP group lost less LBM in the trunk and legs than the NP group. These sex and protein intake responses resulted in the NP men losing the most LBM in the legs and the NP women losing the most LBM in the trunk. Over time, men lost more FM (-5.0 vs -3.9 kg) from the trunk and less from legs (-1.7 vs -2.1 kg) than women (P < .05), which resulted in a greater decrease of the android-to-gynoid fat ratio for the men. Protein intake did not influence these sex-specific responses or have any independent effects on changes in FM. In addition, protein intake did not influence bone mineral density responses over time; bone mineral density was reduced in women, but not in men. These findings indicate that higher protein intake during weight loss promotes the retention of LBM in both the trunk and legs despite the sex-specific changes in these body regions.

Effect of weight loss and regain on adipose tissue distribution, composition of lean mass and resting energy expenditure in young overweight and obese adults

BACKGROUND

Although weight cycling is frequent in obese patients, the adverse consequences on body composition and an increased propensity to weight gain remain controversial.

OBJECTIVE

We investigated the effect of intentional weight loss and spontaneous regain on fat distribution, the composition of lean mass and resting energy expenditure (REE).

DESIGN

Weight regainers (≥ 30% of loss, n=27) and weight-stable subjects (within <± 20% of weight change, n=20) were selected from 103 overweight and obese subjects (body mass index 28-43 kg m(-2), 24-45 years) who passed a 13-week low-calorie diet intervention. REE and body composition (by densitometry and whole-body magnetic resonance imaging) were examined at baseline, after weight loss and at 6 months of follow-up.

RESULTS

Mean weight loss was -12.3 ± 3.3 kg in weight-stable subjects and -9.0 ± 4.3 kg in weight regainers (P<0.01). Weight regain was incomplete, accounting for 83 and 42% of weight loss in women and men. Regain in total fat and different adipose tissue depots was in proportion to weight regain except for a higher regain in adipose tissue of the extremities in women and a lower regain in extremity and visceral adipose tissue in men. In both genders, regain in skeletal muscle of the trunk lagged behind skeletal muscle regain at the extremities. In contrast to weight-stable subjects, weight regainers showed a reduced REE adjusted for changes in organ and tissue masses after weight loss (P<0.001).

CONCLUSION

Weight regain did not adversely affect body fat distribution. Weight loss-associated adaptations in REE may impair weight loss and contribute to weight regain.

Addressing weight loss recidivism: a clinical focus on metabolic rate and the psychological aspects of obesity

Obesity in the United States has reached epidemic proportions and has become an unprecedented public health burden. This paper returns to the evidence for metabolic rate set points and emphasizes the clinical importance of addressing changes in metabolic rate throughout the weight loss process. In addition to the importance of clinically attending to the modulation of metabolic rate, the psychological aspects of obesity are addressed as part of the need to holistically treat obesity.

Influence of resting energy expenditure on blood pressure is independent of body mass and a marker of sympathetic tone

Two recent examinations reported a strong association between blood pressure (BP) and resting energy expenditure (REE), independent of body mass and body composition. Both reports postulate that neurohumoral processes that contribute to variation in REE may partly mediate the body mass effect on BP. Therefore, we examined the relationship of REE and BP in 108 asymptomatic women (a) to confirm previous findings in a novel population and (b) to examine the impact of a marker of sympathetic tone on this relationship, as this was indicated as a potentially salient intermediary in previous reports. All testing was performed during a 4-day admission to the General Clinical Research Center. Resting energy expenditure was measured by indirect calorimetry, body composition was determined by dual-energy x-ray absorptiometry, and 24-hour fractionated urinary norepinephrine was determined by high-performance liquid chromatography. Multiple linear regression revealed REE as a significant predictor of systolic BP (β = 0.30, P = .04), independent of race (β = 0. 28, P = .01), age (β = -0.02, P = .80), height (β = -0.38, P = .08), fat mass (β = 0.22, P = .20), fat-free mass (β = 0.08, P = .65), and 24-hour fractionated urinary norepinephrine (β = 0.06, P = .57); and the same model using diastolic BP as the dependent variable approached significance (β = 0.24, P = .09). This study affirms previous findings that REE may be a potential mediator in resting BP, independent of many well-cited factors and, additionally, a marker of sympathetic tone.

Body fat and racial genetic admixture are associated with aerobic fitness levels in a multiethnic pediatric population

Aerobic fitness and adiposity are each independently associated with health outcomes among children, although the relationship between these two variables is unclear. Our objectives were to evaluate (i) the association of adiposity with aerobic fitness using objectively measured levels of percent body fat, compared to BMI as a percentile proxy for adiposity while controlling for genetic admixture, and (ii) the congruence of BMI categories with high and low body fat categories of objectively measured percent body fat. Participants were 232 African-American (AA), European-American (EA), and Hispanic-American (HA) children aged 7-12 years (Tanner stage <3). Aerobic fitness was measured via a submaximal indirect calorimetry treadmill test (VO(2-170)), and physical activity levels with accelerometry. Genetic admixture estimates were obtained using 140 genetic ancestry informative markers to estimate European, African, and Amerindian admixture. Fat mass was determined using dual-energy x-ray absorptiometry (DXA). Children were classified into a low body fat group (<25% in males, <30% in females) or a high body fat group based on their percent body fat; children were also categorized according to BMI percentile. Children in the low body fat group had significantly higher aerobic fitness (P < 0.05) regardless of BMI percentile classification. Higher African genetic admixture was associated with lower aerobic fitness (P < 0.05), while physical activity was positively associated with fitness (P < 0.01). In conclusion, aerobic fitness levels differ by percent body fat and genetic admixture irrespective of BMI classification, and such differences should be taken into account when evaluating outcomes of health interventions.

Associations of free fatty acids with insulin secretion and action among African-American and European-American girls and women

Ethnic differences in insulin secretion and action between African Americans (AAs) and European Americans (EAs) may influence mobilization of free fatty acids (FFAs). We tested the hypotheses that FFA concentrations would be associated with measures of insulin secretion and action before and during a glucose challenge test. Subjects were 48 prepubertal girls, 60 premenopausal women, and 46 postmenopausal women. Fasting insulin (insulin(0)), the acute insulin response to glucose (AIR(g)), the insulin sensitivity index (S(I)), basal and nadir FFA (FFA(0), FFA(nadir)), and nadir time (TIME(nadir)) were determined during an intravenous glucose tolerance test (IVGTT). Stepwise multiple linear regression (MLR) analysis was conducted to identify associations of FFA(0), FFA(nadir), and TIME(nadir) with ethnicity, age group, insulin measures, indexes of body composition from dual-energy X-ray absorptiometry, and measures of fat distribution from computed tomography scan. In this population, insulin(0) and AIR(g) were higher among AAs vs. EAs, whereas S(I) was lower, independent of age group. MLR analyses indicated that FFA(0) was best predicted by lean tissue mass (LTM), leg fat mass, ethnicity (lower in AAs), S(I), and insulin(0). FFA(nadir) was best predicted by FFA(0), age group, and intra-abdominal adipose tissue (IAAT). TIME(nadir) was best predicted by leg fat mass, AIR(g), and S(I). In conclusion, indexes of insulin secretion and action were associated with FFA dynamics in healthy girls and women. Lower FFA(0) among AAs was independent of insulin(0) and S(I). Whether lower FFA(0) is associated with substrate oxidation or risk for obesity remains to be determined.

Resting energy expenditure changes with weight loss: racial differences

It is controversial whether weight loss reduces resting energy expenditure (REE) to a different magnitude in black and white women. This aim of this study was to determine whether changes in REE with weight loss were different between black and white postmenopausal women, and whether changes in body composition (including regional lean and fat mass) were associated with REE changes within each race. Black (n = 26) and white (n = 65) women (age = 58.2 +/- 5.4 years, 25 < BMI < 40 kg/m(2)) completed a 20-week weight-loss intervention. Body weight, lean and fat mass (total body, limb, and trunk) via dual-energy X-ray absorptiometry, and REE via indirect calorimetry were measured before and after the intervention. We found that baseline REE positively correlated with body weight, lean and fat mass (total, limb, and trunk) in white women only (P < 0.05 for all). The intervention decreased absolute REE in both races similarly (1,279 +/- 162 to 1,204 +/- 169 kcal/day in blacks; 1,315 +/- 200 to 1,209 +/- 185 kcal/day in whites). REE remained decreased after adjusting for changes in total or limb lean mass in black (1,302-1,182 kcal/day, P = 0.043; 1,298-1,144 kcal/day, P = 0.006, respectively), but not in white, women. Changes in REE correlated with changes in body weight (partial r = 0.277) and fat mass (partial r = 0.295, 0.275, and 0.254 for total, limb, and trunk, respectively; P < 0.05) independent of baseline REE in white women. Therefore, with weight loss, REE decreased in proportion to the amount of fat and lean mass lost in white, but not black, women.

Contribution of individual organ mass loss to weight loss-associated decline in resting energy expenditure

BACKGROUND

Weight loss leads to reduced resting energy expenditure (REE) independent of fat-free mass (FFM) and fat mass (FM) loss, but the effect of changes in FFM composition is unclear.

OBJECTIVE

We hypothesized that a decrease in REE adjusted for FFM with weight loss would be partly explained by a disproportionate loss in the high metabolic activity component of FFM.

DESIGN

Forty-five overweight and obese women [body mass index (in kg/m(2)): 28.7-46.8] aged 22-46 y followed a low-calorie diet for 12.7 +/- 2.2 wk. Body composition was measured by magnetic resonance imaging, dual-energy X-ray absorptiometry, and a 4-compartment model. REE measured by indirect calorimetry (REEm) was compared with REE calculated from detailed body-composition analysis (REEc) by using specific organ metabolic rates (ie, organ REE/mass).

RESULTS

Weight loss was 9.5 +/- 3.4 kg (8.0 +/- 2.9 kg FM and 1.5 +/- 3.1 kg FFM). Decreases in REE (-8%), free triiodothyronine concentrations (-8%), muscle (-3%), heart (-5%), liver (-4%), and kidney mass (-6%) were observed (all P < 0.05). Relative loss in organ mass was significantly higher (P < 0.01) than was the change in low metabolically active FFM components (muscle, bone, and residual mass). After weight loss, REEm - REEc decreased from 0.24 +/- 0.58 to 0.01 +/- 0.44 MJ/d (P = 0.01) and correlated with the decrease in free triiodothyronine concentrations (r = 0.33, P < 0.05). Women with high adaptive thermogenesis (defined as REEm - REEc < -0.17 MJ/d) had less weight loss and conserved FFM, liver, and kidney mass.

CONCLUSIONS

After weight loss, almost 50% of the decrease in REEm was explained by losses in FFM and FM. The variability in REEm explained by body composition increased to 60% by also considering the weight of individual organs.

Ethnic differences in body composition and anthropometric characteristics in Australian Caucasian and urban Indigenous children

The objective was to compare ethnic differences in anthropometry, including size, proportions and fat distribution, and body composition in a cohort of seventy Caucasian (forty-four boys, twenty-six girls) and seventy-four urban Indigenous (thirty-six boys, thirty-eight girls) children (aged 9–15 years). Anthropometric measures (stature, body mass, eight skinfolds, thirteen girths, six bone lengths and five bone breadths) and body composition assessment using dual-energy X-ray absorptiometry were conducted. Body composition variables including total body fat percentage and percentage abdominal fat were determined and together with anthropometric indices, including BMI (kg/m2), abdominal:height ratio (AHtR) and sum of skinfolds, ethnic differences were compared for each sex. After adjustment for age, Indigenous girls showed significantly (P < 0·05) greater trunk circumferences and proportion of overweight and obesity than their Caucasian counterparts. In addition, Indigenous children had a significantly greater proportion (P < 0·05) of trunk fat. The best model for total and android fat prediction included sum of skinfolds and age in both sexes (>93 % of variation). Ethnicity was only important in girls where abdominal circumference and AHtR were included and Indigenous girls showed significantly (P < 0·05) smaller total/android fat deposition than Caucasian girls at the given abdominal circumference or AHtR values. Differences in anthropometric and fat distribution patterns in Caucasian and Indigenous children may justify the need for more appropriate screening criteria for obesity in Australian children relevant to ethnic origin.

Resistance training conserves fat-free mass and resting energy expenditure following weight loss

OBJECTIVE

To determine what effect diet-induced approximately 12 kg weight loss in combination with exercise training has on body composition and resting energy expenditure (REE) in premenopausal African-American (AA) and European-American (EA) women.

METHODS AND PROCEDURES

This study was a longitudinal, randomized weight loss clinical intervention, with either aerobic (AT), resistance (RT), or no exercise training (NT). Forty-eight AA and forty-six EA premenopausal overweight (BMI between 27 and 30) women underwent weight loss to a BMI<25. Body composition (densitometry), REE (indirect calorimetry), maximal oxygen uptake (VO2max), and muscular strength (isometric elbow flexion) were evaluated when subjects were in energy balance.

RESULTS

AA women lost less fat-free mass (FFM, P<or=0.05) (47.0+/-4.6 to 46.9+/-5.0 kg) than EA women (46.4+/-4.9 to 45.2+/-4.6 kg). Regardless of race, RT maintained FFM (P<or=0.05) following weight loss (46.9+/-5.2 to 47.2+/-5.0 kg) whereas AT (45.4+/-4.2 to 44.4+/-4.1 kg) and NT (47.9+/-4.7 to 46.4+/-5.1 kg) decreased FFM (P<or=0.05). Both AT and NT decreased in REE with weight loss but RT did not. Significant time by group interactions (all P<or=0.05) for strength indicated that RT maintained strength and AT did not.

DISCUSSION

AA women lost less FFM than EA women during equivalent weight losses. However, following weight loss in both AA and EA, RT conserved FFM, REE, and strength fitness when compared to women who AT or did not train.

Is lean body mass decreased after obesity treatment by adjustable gastric banding?

BACKGROUND

There is concern that surgically-induced weight loss in obese subjects is associated with a disproportionate decrease in lean body mass (LBM) and in skeletal muscle mass (SMM), a major constituent of LBM. To address this issue, 1) we measured total and regional body composition following gastric banding in a group of obese subjects, and 2) we compared these data to those of a non-surgical control group of similar age and body size.

METHODS

Body composition was assessed by dual-energy X-ray absorptiometry (DEXA) before and after laparoscopic adjustable silicone gastric banding (LAGB) in 32 women (after 1 year: age 43.7+/-8.4 years, BMI 36.4+/-5.9 kg/m2, mean+/-SD), and in 117 control women (age 44.5+/-7.5 years; BMI 36.7+/-5.5 kg/m2) referred for non-surgical weight management, prior to weight loss. SMM was estimated using a published equation based on LBM of the extremities (appendicular LBM).

RESULTS

1 year after LAGB, body weight loss (-23.7+/-11.6 kg, P<10(-6)) was mainly due to decreased fat mass (-21.2+/-11.2 kg, P<10(-6)), and total LBM was modestly, although significantly, decreased (-2.1+/-4.2 kg, P=0.01). Appendicular LBM (-0.7+/-2.7 kg) and total SMM (-0.9+/-3.0 kg) were not significantly modified. None of the body composition variables was significantly decreased in weight-reduced subjects compared to the control group, especially appendicular LBM and total SMM.

CONCLUSIONS

Results provide no evidence for a decrease in appendicular LBM and total SMM with weight loss following LAGB. Follow-up of these obese patients revealed a very favorable pattern of change in total and regional body composition, with preservation of muscle mass.

Ability of the Harris Benedict formula to predict energy requirements differs with weight history and ethnicity

The objective of this study was to assess the effects of weight history status and ethnicity on the ability of the Harris Benedict (HB) formula to: 1) predict measured resting energy expenditure (REE), and, 2) accurately estimate energy needs over a 2-week test period. Subjects were never-overweight (BMI </= 25 kg/m(2), n=47), overweight (BMI 27-30 kg/m(2), n=170), and weight-reduced (BMI </= 25 kg/m(2), n=51) healthy, adult African-American (AA) and Caucasian (C) women. Food was provided for 2 weeks at an energy level calculated using the HB formula multiplied by a 1.35 activity factor. After 2 weeks, weight, REE (by indirect calorimetry), and body composition (by dual-energy X-ray absorptiometry) were assessed. Data were analyzed using 2-way ANOVA at p<0.05 significance. The HB formula overestimated REE 1) in each weight history group (by 160 +/-125 kcals among never-overweight, 295 +/-189 kcal among overweight, and 105 +/-135 among weight-reduced) such that there was a group effect on overestimation (P<0.001) and 2) between ethnicities, with a greater overestimation in AA vs. C (P<0.001). There was a significant effect of weight history group on weight change (P<0.001) over 2-weeks, such that weight-reduced women gained more weight than the other two groups (P<0.05). In conclusion, the ability of the HB formula to estimate REE differed with weight history status and ethnicity. The accuracy of the HB formula to predict dietary energy needs was affected by weight history status. These results suggest that formulas used to calculate energy needs should take into account weight history and ethnicity.

Increased resting energy expenditure after 40 minutes of aerobic but not resistance exercise

OBJECTIVE

Resting energy expenditure (REE) is increased 24 hours after high-intensity aerobic exercise lasting 60 minutes, whereas results have been inconsistent after resistance training and aerobic exercise of shorter duration. The objective of the study was to compare the effects of 40 minutes of high-intensity aerobic vs. resistance exercise on REE 19 to 67 hours after exercise.

RESEARCH METHODS AND PROCEDURES

REE was compared 19, 43, and 67 hours after 40 minutes of aerobic training (AT; 80% maximum heart rate) or resistance training (RT; 10 repetitions at 80% maximum strength, two sets and eight exercises). Twenty-three black and 22 white women were randomly assigned to AT, RT, or no training (controls). Exercisers trained 25 weeks. REE was measured after a 12-hour fast.

RESULTS

There was a significant time x group interaction for REE when adjusted for fat-free mass and fat mass, with post hoc tests revealing that the 50-kcal difference between 19 and 43 hours (1310 +/- 196 to 1260 +/- 161 kcal) and the 34-kcal difference between 19 and 67 hours (1310 +/- 196 to 1276 +/- 168 kcal) were significant for AT. No other differences were found, including RT (19 hours, 1256 +/- 160; 43 hours, 1251 +/- 160; 67 hours, 1268 +/- 188 kcal). Urine norepinephrine increased with training only in AT. After adjusting for fat-free mass, REE Delta between 19 and both 43 and 67 hours was significantly related to urine norepinephrine (r = 0.76, p < 0.01 and 0.68, p < 0.03, respectively).

DISCUSSION

Consistent with findings on longer duration AT, these results show that 40 minutes of AT elevates REE for 19 hours in trained black and white women. This elevation did not occur with 40 minutes of RT. Results suggest that differences are, in part, due to increased sympathetic tone.

Weight loss strategies for obese adults: personalized weight management program vs. standard care

OBJECTIVE

The objective of this study was to evaluate the effect of a 32-week personalized Polar weight management program (PWMP) compared with standard care (SC) on body weight, body composition, waist circumference, and cardiorespiratory fitness in overweight or obese adults.

RESEARCH METHODS AND PROCEDURES

Overweight or obese (29 +/- 2 kg/m(2)) men and women (n = 74) 38 +/- 5 years of age were randomly assigned into either PWMP (men = 20, women = 21) or SC (men = 15, women = 18). Both groups managed their own diet and exercise program after receiving the same standardized nutrition and physical activity advice. PWMP also received a weight management system with literature to enable the design of a personalized diet and exercise weight loss program. Body weight and body composition, waist circumference, and cardiorespiratory fitness were measured at weeks 0, 16, and 32.

RESULTS

Eighty percent of participants completed the 32-week intervention, with a greater proportion of the dropouts being women (PWMP: 2 men vs. 7 women; SC: 2 men vs. 4 women). At 32 weeks, PWMP completers had significantly (p < 0.001) greater losses in body weight [6.2 +/- 3.4 vs. 2.6 +/- 3.6 (standard deviation) kg], fat mass (5.9 +/- 3.4 vs. 2.2 +/- 3.6 kg), and waist circumference (4.4 +/- 4.5 vs. 1.0 +/- 3.6 cm). Weight loss and fat loss were explained by the exercise energy expenditure completed and not by weekly exercise duration.

DISCUSSION

More effective weight loss was achieved after treatment with the PWMP compared with SC. The results suggest that the PWMP enables effective weight loss through tools that support self-monitoring without the requirement of more costly approaches to program supervision.

The role of diet and exercise for the maintenance of fat-free mass and resting metabolic rate during weight loss

The incidence of obesity is increasing rapidly. Research efforts for effective treatment strategies still focus on diet and exercise programmes, the individual components of which have been investigated in intervention trials in order to determine the most effective recommendations for sustained changes in bodyweight. The foremost objective of a weight-loss trial has to be the reduction in body fat leading to a decrease in risk factors for metabolic syndrome. However, a concomitant decline in lean tissue can frequently be observed. Given that fat-free mass (FFM) represents a key determinant of the magnitude of resting metabolic rate (RMR), it follows that a decrease in lean tissue could hinder the progress of weight loss. Therefore, with respect to long-term effectiveness of weight-loss programmes, the loss of fat mass while maintaining FFM and RMR seems desirable. Diet intervention studies suggest spontaneous losses in bodyweight following low-fat diets, and current data on a reduction of the carbohydrate-to-protein ratio of the diet show promising outcomes. Exercise training is associated with an increase in energy expenditure, thus promoting changes in body composition and bodyweight while keeping dietary intake constant. The advantages of strength training may have greater implications than initially proposed with respect to decreasing percentage body fat and sustaining FFM. Research to date suggests that the addition of exercise programmes to dietary restriction can promote more favourable changes in body composition than diet or physical activity on its own. Moreover, recent research indicates that the macronutrient content of the energy-restricted diet may influence body compositional alterations following exercise regimens. Protein emerges as an important factor for the maintenance of or increase in FFM induced by exercise training. Changes in RMR can only partly be accounted for by alterations in respiring tissues, and other yet-undefined mechanisms have to be explored. These outcomes provide the scientific rationale to justify further randomised intervention trials on the synergies between diet and exercise approaches to yield favourable modifications in body composition.

Metabolic equivalent: one size does not fit all

The metabolic equivalent (MET) is a widely used physiological concept that represents a simple procedure for expressing energy cost of physical activities as multiples of resting metabolic rate (RMR). The value equating 1 MET (3.5 ml O2·kg−1·min−1 or 1 kcal·kg−1·h−1) was first derived from the resting O2 consumption (V̇o2) of one person, a 70-kg, 40-yr-old man. Given the extensive use of MET levels to quantify physical activity level or work output, we investigated the adequacy of this scientific convention. Subjects consisted of 642 women and 127 men, 18–74 yr of age, 35–186 kg in weight, who were weight stable and healthy, albeit obese in some cases. RMR was measured by indirect calorimetry using a ventilated hood system, and the energy cost of walking on a treadmill at 5.6 km/h was measured in a subsample of 49 men and 49 women (26–45 kg/m2; 29–47 yr). Average V̇o2 and energy cost corresponding with rest (2.6 ± 0.4 ml O2·kg−1·min−1 and 0.84 ± 0.16 kcal·kg−1·h−1, respectively) were significantly lower than the commonly accepted 1-MET values of 3.5 ml O2·kg−1·min−1 and 1 kcal·kg−1·h−1, respectively. Body composition (fat mass and fat-free mass) accounted for 62% of the variance in resting V̇o2 compared with age, which accounted for only 14%. For a large heterogeneous sample, the 1-MET value of 3.5 ml O2·kg−1·min−1 overestimates the actual resting V̇o2 value on average by 35%, and the 1-MET of 1 kcal/h overestimates resting energy expenditure by 20%. Using measured or predicted RMR (ml O2·kg−1·min−1 or kcal·kg−1·h−1) as a correction factor can appropriately adjust for individual differences when estimating the energy cost of moderate intensity walking (5.6 km/h).

Metabolic risk factors in formerly obese women--effects of a pronounced weight loss by gastric band operation compared with weight loss by diet alone

AIM

The aim of the present study was to evaluate differences in the metabolic risk profile in formerly obese women, in whom a significant weight loss was obtained by Swedish adjustable gastric band (SAGB) operation or by diet alone.

METHODS

A total of 40 patients (24 after SAGB and 16 after diet) participated in the study. Clinical data, including body mass index (BMI), waist-to-hip ratio, body fat content and blood pressure values, as well as laboratory results [fasting glucose, insulin, homeostasis model assessment (HOMA) index, leptin, lipid values and markers of subclinical inflammation] were evaluated before a planned abdominoplastic operation.

RESULTS

Patients in the SABG group had lost a significantly greater amount of weight (52.7 +/- 10.0 kg) compared with the diet group (20.0 +/- 11.5 kg; p < 0.001), and the percent excess weight loss was 69.1 +/- 11.4 in the SAGB group and 54.5 +/- 17.7 (p < 0.040) in the diet group. Before the abdominoplastic operation neither the mean BMI nor the percentage of fat mass revealed a significant difference between the groups. Fasting insulin (6.1 +/- 3.0 microU/ml) and the HOMA index (1.4 +/- 0.7) as a measure of insulin resistance were significantly lower in the SAGB than in the diet group (fasting insulin: 8.2 +/- 3.8 microU/ml; p < 0.048; HOMA index: 2.0 +/- 1.0; p < 0.031). Swedish adjustable gastric band patients showed significantly lower plasma leptin levels (9.4 +/- 10.8 ng/ml) than the dietary-treated patients (13.9 +/- 9.6 ng/ml; p < 0.014), while tumour necrosis factor-alpha serum levels were increased in the SAGB group (17.6 +/- 7.3 pg/ml) compared with the diet group (11.9 +/- 0.49 pg/l; p < 0.048).

CONCLUSIONS

The extensive weight loss in formerly obese women after SAGB operation was paralleled by a favourable metabolic profile indicating a higher degree of insulin sensitivity than in women after a successful, but less pronounced weight loss by diet alone.

Low relative resting metabolic rate and body weight gain in adult Caucasian Italians

OBJECTIVE

To investigate the relationship between resting metabolic rate (RMR) and subsequent changes in body size and degree of fatness in a group of adult Caucasian Italians.

DESIGN

Prospective, longitudinal, observational study.

SUBJECTS

In total, 155 subjects (72 males and 83 females, age range: 18-55 y; BMI: 17.5-63.4 kg/m2) were evaluated. In total, 43 (26 m and 17 f; BMI: 28.9+/-1.1 kg/m2, mean+/-s.e.m.) of them were reassessed 10-12 y later.

MEASUREMENTS

Anthropometric and body composition (bioimpedance analysis) parameters and RMR (indirect calorimetry) were taken at baseline and after 10-12 y.

RESULTS

Subjects (15 m, 8 f) who gained body weight (arbitrarily defined as a change in body weight > or = 5 kg) had baseline BMI (29.9+/-1.8 vs 28.0+/-1.4; P = NS) and body composition in terms of fat mass (FM%) and fat-free mass (FFM kg) comparable to those of the subjects (11 m, 9 f) whose body weight remained stable. Baseline RMR was significantly lower in subjects who gained weight than in those who did not (108+/-2.1 vs 122+/-3.1 kJ/kg-FFM 24 h; P < 0.001), although it did not differ significantly between the two groups (119+/-2 vs 121+/-2 kJ/kg-FFM 24 h; P = NS) 10-12 y later. Baseline RMR was inversely correlated to both change in body weight (r = -0.57; P < 0.001) and FM (r = -0.50; P < 0.001).

CONCLUSION

A low RMR normalized for FFM appears to be associated with body weight gain in the long run in adult Caucasian Italians.